selected-outline-item

Arguments:
outline

Returns the outline-item that is currently
selected in outline (which should be an instance
of the outline
class), or nil if no item is selected. If
the multiple-selections property of the
outline is currently true, then a list of zero or
more outline-items is returned instead.

The value of this
outline-item
(or the list of the values of multiple items) is also the value of the outline itself. It is
more efficient to pass an outline-item rather than its value
to some outline functions.

The selected item is usually the same as the focused-outline-item, but not if
scrolling with the keyboard has focused on an item that is in view
without changing the selected item.